Incorrect. Atheism is a denial (active stand) that there is a god (e.g. “there ain’t no such critter”). It isn’t a passive stand.

ideclare writes: “I believe that if a deity exists, it might be possible to prove to me that it exists. Therefore I am not an agnostic; I am an atheist.”

You just contradicted yourself. The atheist is hard-over in his denial. If you feel there’s a possibility that a god can exist (and just waiting for convincing argument), then you’ve just crossed into agnostic territory.